Imaging system and components thereof

ABSTRACT

In one embodiment, a camera includes an image sensor, a sheath, and a housing. A first end of the sheath is closed to form a cavity to accommodate the image sensor, and the housing is adapted to mate with a second end of the sheath. One of the housing and the second end of the sheath includes at least one tab, and the other of the housing and the second end of the sheath includes at least one slot, the at least one tab being adapted to mate with the at least one slot when the housing is mated with the second end of the sheath to inhibit the second end of the sheath from rotating with respect to the housing. In another embodiment, a camera includes a sheath, an image sensor, and a support. The support, which is at least partially disposed within the sheath, supports the image sensor within the sheath such that the image sensor is rotatable about at least two axes of rotation with respect to the sheath through a range of orientations, wherein an imaging axis of the image sensor is oriented normal to an inner surface of the sheath throughout the image sensor&#39;s range of orientations. In another embodiment, a camera includes a sheath, an image sensor, and at least one light. The image sensor and the at least one light are disposed within the sheath, and the at least one light is adapted to generate sufficient heat to prevent condensation from forming on the sheath when the sheath is inserted into a body of a living patient. In addition, an actuation module for use with a camera, a camera module for use in a camera, and a novel bearing ring assembly are disclosed.

[0001] This application is a continuation-in-part of application Ser.No. 09/065,116, filed Apr. 23, 1998, currently pending, which is acontinuation of application Ser. No. 08/937,238, filed Sep. 16, 1997,now U.S. Pat. No. 5,762,603, which is a continuation of application Ser.No. 08/704,044, filed Aug. 30, 1996, now abandoned, which claims thebenefit of provisional application serial No. 60/003,802, filed Sep. 15,1995.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention is directed to the field of opticalimaging.

[0004] 2. Discussion of Related Art

[0005] Optical imaging systems are used in a wide variety ofapplications. For example, optical imaging systems are used forsurveillance and/or security in residential, commercial, and militarysettings. In the medical field, endoscopic optical imaging systems canbe used for performing surgical and diagnostic procedures inside thebody. Optical imaging systems can also be used in conventionalphotographic applications, such as still photography or video recording.

[0006] In a conventional optical imaging system, the portion of theimaging system that receives light from a target being viewed by thesystem is physically disposed next to other portions of the imagingsystem that store, process, or display the image of the target. Forexample, in a conventional surveillance/security system, a lens, acharge coupled device (CCD) camera, and other electronic components(such as an amplifier, an image processor, etc.) are all disposed withinthe same camera housing. Other portions of the imaging system (e.g.,image storage and/or display) may also be disposed in the camerahousing, or may be disposed in a remote location that is connected tothe camera housing via cables. Because much of the optical imagingsystem is disposed within the camera housing, the camera housing isrelatively large, heavy, and obtrusive.

[0007] In the medical field, due to the small size requirements imposedby invasive surgical and diagnostic procedures, most endoscopic opticalimaging systems include an assembly of optical fibers and a lens that isinserted into the patient. The assembly of optical fibers and the lensrelay light received from the target to the rest of the system (e.g., aCCD camera, amplifiers, an image processor, an image storage device, adisplay, etc.) located outside of the patient. Although this arrangementpermits the portion of the optical imaging system that is inserted intothe patient to be quite small, such optical fiber-based imaging systemsare expensive to purchase and maintain.

SUMMARY OF INVENTION

[0008] One aspect of the present invention is directed to, a cameraincluding an image sensor, a sheath, and a housing. A first end of thesheath is closed to form a cavity to accommodate the image sensor, andthe housing is adapted to mate with a second end of the sheath. One ofthe housing and the second end of the sheath includes at least one tab,and the other of the housing and the second end of the sheath includesat least one slot, the at least one tab being adapted to mate with theat least one slot when the housing is mated with the second end of thesheath to inhibit the second end of the sheath from rotating withrespect to the housing.

[0009] Another aspect of the present invention is directed to a cameraincluding a sheath, an image sensor, and a support. The support, whichis at least partially disposed within the sheath, supports the imagesensor within the sheath such that the image sensor is rotatable aboutat least two axes of rotation with respect to the sheath through a rangeof orientations, wherein an imaging axis of the image sensor is orientednormal to an inner surface of the sheath throughout the image sensor'srange of orientations.

[0010] Another aspect of the present invention is directed to anactuation module for use with a camera including an image sensor that isrotatable about at least two axes of rotation. The actuation moduleincludes a module base, and a pair of actuators. The module base isadapted to be removably mounted in the camera. The pair of actuators ismounted to the base so that the pair of actuators can be removed fromand inserted into the camera as a single unit, each of the pair ofactuators being adapted to rotate the image sensor about a respectiveone of the at least two axes of rotation.

[0011] Another aspect of the present invention is directed to a cameramodule for use in a camera. The camera module includes a module base, animage sensor, a cable, and a signal conditioning circuit. The cable iscoupled to the image sensor, and the signal conditioning circuit iscoupled to the cable to receive an electronic signal produced by theimage sensor via the cable. Each of the image sensor, the cable, and thesignal conditioning circuit is mounted to the base, and the base isadapted to be removably mounted in the camera, whereby the image sensor,the cable, the signal conditioning circuit, and the base are removablefrom and insertable into the camera as a single unit.

[0012] Another aspect of the present invention is directed to a cameraincluding a sheath, an image sensor, and at least one light. The imagesensor and the at least one light are disposed within the sheath, andthe at least one light is adapted to generate sufficient heat to preventcondensation from forming on the sheath when the sheath is inserted intoa body of a living patient.

[0013] Another aspect of the present invention is directed to a bearingring assembly including first and second rings, and a plurality of ballbearings. The second ring is arranged concentrically with the firstring, and the ball bearings are disposed between the first and secondrings such that the first ring is permitted to rotate with respect tothe second ring. The first ring includes at least one first matingfeature adapted to engage a first structure so that the at first ring isinhibited from rotating with respect to the first structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a block diagram showing an example of an imaging systemconfigured in accordance with one embodiment of the present invention;

[0015]FIG. 2 shows an example of a camera, which may be used in theimaging system of FIG. 1, in accordance with another embodiment of theinvention;

[0016]FIG. 3 is an exploded view of the camera of FIG. 2;

[0017]FIG. 4 illustrates an exemplary implementation of an upper housingof the camera of FIGS. 2-3 in accordance with one embodiment of theinvention;

[0018]FIG. 5 illustrates an exemplary implementation of an actuatormodule of the camera of FIGS. 2-3 in accordance with one embodiment ofthe invention;

[0019]FIGS. 6a-b illustrates an exemplary implementation of a bearingring assembly of the camera of FIGS. 2-3 in accordance with oneembodiment of the invention;

[0020]FIG. 7 shows an illustrative embodiment of the distal end of thecamera of FIGS. 2-3 wherein the distal end includes components forpositioning the viewing elements of the camera;

[0021]FIG. 8 illustrates an exemplary lighting system that may be usedto illuminate a viewing area of the camera of FIGS. 2-3 in accordancewith one embodiment of the invention;

[0022]FIG. 9 shows an illustrative implementation of a camera module ofthe camera of FIGS. 2-3 in accordance with one embodiment of theinvention;

[0023] FIGS. 10-11 shows an illustrative implementation of a lensassembly of the camera of FIGS. 2-3 in accordance with one embodiment ofthe invention;

[0024]FIG. 12 shows an example of a foot pedal control assembly that maybe employed as the camera remote control of FIG. 1 in one embodiment ofthe invention;

[0025] FIGS. 13-15 show an example of a hand-operated remote controlthat may be employed as the camera remote control of FIG. 1 inaccordance with another embodiment of the invention; and

[0026]FIG. 16 shows an example of a voice-activated remote-control thatmay be employed as the camera remote-control of FIG. 1 in accordancewith yet another embodiment of the invention.

DETAILED DESCRIPTION

[0027]FIG. 1 shows an example of an imaging system 100 according to oneembodiment of the present invention. As shown in FIG. 1, the imagingsystem 100 includes a camera controller 102 (including a display 104), acamera 106, and a camera remote-control 108.

[0028] In the illustrative embodiment of FIG. 1, the camera 106 includesa camera head 122 (including an image sensor 124 and a lens assembly128), a signal-conditioning circuit 120, and one or more actuator(s)118. In operation, an optical image viewed by the camera head 122 isfocused by the lens assembly 128 onto the image sensor 124, and theimage sensor 124 converts the received image into electrical signalswhich are transmitted to the signal conditioning circuit 120 via aconnection 134. The signal conditioning circuit 120 processes thesignals received from the image sensor 124, and transmits processedsignals representing the sensed image (via a communication link 130) tothe camera controller 102 for display to a user on the display 104. Bymanipulating the camera remote-control 108, the user may cause signalsto be transmitted (via the camera controller 102 and the communicationlink 130) to the actuator(s) 118 to cause the actuator(s) 118 to adjusta physical position of the camera head 122, thereby controlling theimage displayed on the display 104.

[0029] In the FIG. 1 example, the camera 106 is coupled to the cameracontroller 102 via the communication link 130 so that the camera 106 maybe disposed remotely from the camera controller 102 and the cameraremote-control 108. The communication link 130 may be implemented in anyof numerous ways, and the invention is not limited to the use of anyparticular type of communication link. For example, the communicationlink 130 may be implemented using a standard multi-conductor cable, asingle cable on which multiple signals are multiplexed, or a wirelesscommunication link (e.g., a radio-frequency (RF) or infrared (IR)communication link). Also, the communication link 130 can be virtuallyany length, and the invention is not limited to the use of acommunication link of any particular length. For example, thecommunication link 130 may be relatively short (requiring the cameracontroller 102 to be located in the same room as the camera 106), or maytraverse longer distances, e.g., from room-to-room,building-to-building, state-to-state, or country-to-country.

[0030] As shown in FIG. 1, the camera controller 102 may comprise aprogrammed computer (including a processor 110, one or more user-inputdevices 112, a memory 114, a printer 116, and the display 104). Thememory 114 may store a computer program (e.g., software or firmware)which, when executed by the processor 110, cause the processor 110 toperform the various functions described herein. It should beappreciated, however, that the camera controller 102 may be configuredin any of numerous ways, and that the invention is not limited to theuse of a programmed computer such as that shown in FIG. 1. Inalternative embodiments, for example, the camera controller 102 may alsocomprise dedicated hardware, alone or in combination with a programmedprocessor. It should also be understood that, in some embodiments, theimage generated by the image sensor 124 can be displayed on devices thatare driven by circuits other than the processor 102, such that theinvention is not limited to the use of a processor-driven display suchas that shown in FIG. 1. For example, the display 104 may alternativelybe coupled directly to the signal conditioning circuit 120 to display animage based on the signal therefrom.

[0031] Additionally, in some embodiments, the camera remote control 108can be coupled directly to the actuator(s) 118 without passing throughthe processor 110, e.g., when signals from the camera remote-control 108are not required to be converted/translated before being passed to theactuator(s) 118. In embodiments wherein the display 104 and the cameraremote-control 108 do not pass through a common processor, a simpleinterface unit (not shown) may be used to provide a common connectionpoint for the display 104, the camera remote control 108, and the camera106 so that only a single cable or other transmission medium is neededto couple the camera 106 to the other components (via such an interfaceunit), thereby eliminating the cable clutter that would result if aseparate cable were used to connect each of the display 104 and thecamera remote control 108 to the camera 106.

[0032] The display 104 may be a general-purpose video display, atelevision display, a liquid-crystal display (LCD), or any other devicesuitable for displaying an image generated by the camera 106. In someembodiments, the memory 114 (e.g., a random access memory (RAM), diskdrive, tape drive, writeable compact disk (CD) drive, etc.) of thecamera controller 102 can be used to digitally store one or more imagesgenerated by the camera 106. Alternatively, an analog storage device,e.g., a video camera recorder (VCR) (not shown), may be used to store avideo signal generated by the camera 106. In either case, the storedimage may later be displayed on the display 104, or may be displayedand/or stored at a remote location either by transmitting (e.g., over anetwork such as the Internet, or via a point-to-point communicationlink) the stored image to the remote location, or by transporting thestorage medium (e.g., a CD, diskette, magnetic tape, VCR tape, etc.) onwhich the image is stored to the remote location.

[0033] The camera remote-control 108 may be configured in any ofnumerous ways, and the invention is not limited to any particular typeof remote-control device. In one illustrative embodiment, for example,the camera remote-control 108 is a foot pedal control assembly 1202 (seeFIG. 12) including a group of foot-activated switches with which theuser may control the camera head 122. This and other implementations ofthe camera remote-control 108 are described below in connection withFIGS. 12-16.

[0034] With respect to the camera 106, the actuator(s) 118 which causethe camera head 122 to move physically may be any device(s) that arecapable of performing this function. In one illustrative embodiment, forexample, the actuator(s) 118 include a pair of step motors which, inresponse to electrical signals from the camera controller 102, cause theelevation or azimuth of the camera head 122 to be adjusted, depending onwhich motor is activated. It should be appreciated, however, that theinvention is not limited in this respect, and that actuators other thanstep motors (e.g., solenoid actuators) may alternatively be used.

[0035] As shown in FIG. 1, the actuator(s) 118 may be physically linkedto the camera head 122 via one or more mechanical links 132 so thatphysical forces generated by the actuator(s) 118 can be transferred tothe camera head 122 via these links. In such an embodiment, the use ofone or more elongated structures as the mechanical link(s) 132 permitsthe camera head 122 to be disposed remotely from the actuator(s) 118 bya distance equal to the length of the mechanical link(s) 132. In oneillustrative embodiment, the mechanical link(s) 132 are configured suchthat the actuator(s) 118 and the camera head 122 are located,respectively, at proximal and distal ends of the camera 106. In such anembodiment, the distal end of the camera 106 can be made quite smallsince it need not accommodate the actuator(s) 118 as well as the camerahead 122.

[0036] As mentioned above, in the illustrative embodiment of FIG. 1, thecamera head 122 is coupled to the signal conditioning circuit 120 viathe connection 134 so that electrical signals can be transmitted fromthe camera head 122 to the signal conditioning circuit 120. The use ofthe connection 134 in this manner permits the camera head 122 to bedisposed remotely from the signal conditioning circuit 120 by a distanceequal to the length of the connection 134. In one illustrativeembodiment, the camera head 122 is disposed near a distal end of thecamera 106, and the signal conditioning circuit is disposed proximal ofthe camera's distal end. Such an embodiment further enables, thecamera's distal end to be quite small, since it need not accommodate thesignal conditioning circuit 120 along with the camera head 122.

[0037] In one illustrative embodiment, the signal conditioning circuit120 comprises an digital-to-analog converter (DAC) and an amplifier. Insuch an embodiment, the DAC can convert a digital signal generated bythe image sensor 124 into an analog signal, and the amplifier canamplify this analog signal prior to transmitting it to the cameracontroller 102 or other circuitry. In another embodiment, the signalconditioning circuit 120 comprises only an amplifier which amplifies ananalog signal generated by the image sensor 124 prior to transmitting itto the camera controller 102. In either case, the use of an amplifierwithin the signal conditioning circuit 120 permits a relatively lowamplitude signal within the camera 106 to be amplified to a levelsufficient for the processor 110 to digitize with adequate resolution,and/or permits the signal from the camera 106 to be transmitted overlong cable runs or otherwise transmitted over a relatively long distanceto the camera controller 102. It should be appreciated, however, thatthe invention is not limited in this respect, and that thesignal-conditioning circuit 120 may be any of numerous alternative typesof signal-conditioning circuits. In alternative embodiments, forexample, the signal-conditioning circuit 120 may comprise one or morefilters, analog-to-digital converters (ADCs), digital signal processors(DSPs), etc. In fact, in some embodiments, the camera 106 need notinclude any type of signal-conditioning circuit 120, and the signal fromthe image sensor 124 may simply be provided directly to the cameracontroller 102.

[0038] The components of the camera head 122 (i.e., the image sensor 124and the lens assembly 128) may be any of numerous devices suitable forgenerating electrical signals representing an image sensed by the camerahead 122. The image sensor 124 may, for example, include acharge-coupled device (CCD), a metal-oxide semiconductor (MOS) sensor,or a microbolometer (i.e., an infra-red detection array which is capableof perceiving objects at very low levels of light). Alternatively, theimage sensor 124 may include a bundle of fiber optic cables whichchannel light from an image to a remotely-located device that convertsthe light from the cables into electronic signals representing theimage. One example of a lens assembly that may be employed in the camerahead 122 is described below in connection with FIGS. 11 and 12.

[0039] As mentioned above, in the illustrative embodiment of FIG. 1, theimage sensor 124 is coupled to the signal-conditioning circuit 120 viathe connection 134. According to one aspect of the present invention,the signal-conditioning circuit 120, the connection 134, and the camerahead 122 all are included in a single module (i.e., a camera module)that can be removed from the camera 106 as a unit so that the entirecamera module can be removed and replaced with a new camera module whenany one of its component parts fails. The failed camera module may thenbe repaired while enabling the rest of the camera 106 to be used withthe replacement module. An example of a camera module 902 (including asignal conditioning circuit 120 (e.g., an amplifier), a connection 134(e.g., a flexible cable), and a camera head 122) is described below inconnection with FIGS. 8 and 9. The use of such a camera module 902 canbe advantageous, for example, because it is often difficult to determinewhich of the module's component parts have failed, thereby making itquicker and easier to replace the entire module without having toidentify the precise point of failure.

[0040] Similarly, in another embodiment of the invention, all of theactuator(s) 118 are grouped together in a single module (i.e., anactuator module) that can be removed from the camera 106 as a unit sothat the entire actuator module can be removed and replaced with a newactuator module when any one of its component parts fails. An example ofan actuator module 402 is described below in connection with FIGS. 4 and5. Upon the failure of any one of the actuator(s) 118, the entireactuator module may simply be replaced, without having to determinewhich of the actuator(s) 118 has failed, and without having to separatethe failed actuator 118 and gears associated therewith from the workingactuator 118.

[0041] The embodiment of the camera 106 described below includes boththe camera module 902 and the actuator module 402. While the use of bothof these modules can provide significant advantages, it should beappreciated that the present invention is not limited in this respect,as the modules can also be used separately. Furthermore, someembodiments of the invention do not employ any such modules.

[0042] One illustrative embodiment of the camera 106 is shown in FIG. 2.As shown, in the FIG. 2 embodiment, the camera 106 is in the form of anelongated scope, which is useful for endoscopic applications or otherenvironments where access is desired to a remote viewing area through anarrow opening. However, it should be appreciated that the invention isnot limited in this respect, and that the camera 106 may be configuredfor use in any of numerous alternative applications.

[0043] The illustrative embodiment of FIG. 2 may be used, for example,in endoscopic applications by inserting a distal end 204 of the camera106 through an incision in a torso 200 of a human body so that theinternal portion of the torso 200 can be viewed by the camera head 122.In alternative embodiments, the camera 106 may instead be used to viewthe internal portions of any other type of cavity, e.g., a cargo hold, apipe line, a room under surveillance, etc. In the embodiment shown inFIG. 2, the camera head 122 is located adjacent the distal end 204 ofthe camera 106, the actuator(s) 118 are located inside an upper housing202 at a proximal end 208 of the camera 106, and the signal-conditioningcircuit 120 is located in a section 206 therebetween. In the FIG. 2embodiment, the significant physical separation of the camera head 122from both the signal conditioning circuit 120 and the actuator(s) 118 isenabled by the use of an elongated cable as the connection 134 (FIG. 1),and by the use of elongated structures as the mechanical links 132 (FIG.1). That is, the use of an elongated cable as the connection 134 permitsthe signal conditioning circuit 120 to be separated from the camera head122, and the use of elongated structures as the mechanical links 132permits the actuator(s) 118 (in the upper housing 202) to be separatedfrom the camera head 122.

[0044] In the illustrative embodiment of FIG. 2, the physical separationbetween the camera head 122 and the other components of the camera 106permits the distal end 204 to be only wide enough to accommodate thecamera head 122, without also having to accommodate the actuator(s) 118.In this manner, the distal end 202 may be made very narrow so that thecamera 106 can enter the torso 200 (or other cavity) through a verysmall opening. Alternatively, because of the separation between thecamera head 122 and the other components of the camera 106 (e.g., thesignal conditioning circuit 120 and the actuator(s) 118), a largercamera head 122 can be used in the distal end 204 of the camera 106without increasing the width of the distal end 204. The use of a largercamera head may, for example, permit larger optical elements (e.g., thelens assembly 128 and the image sensor 124) to be used, therebyincreasing image resolution.

[0045] As shown in FIG. 3, the camera 106 may include an elongatedsheath 316, and an elongated support member 314 (to which the camerahead 122 is attached) disposed within the sheath 316. As shown, thecamera 106 may be assembled by inserting a distal end 306 of the supportmember 314 into an opening 308 at a proximal end 310 of the sheath 316.The distal end 306 is inserted into the sheath 316 until the proximalend 310 of the sheath 316 abuts an annular section 320 at a distal end302 of the upper housing 202. When the proximal end 310 contacts theannular section 320, gaps 312 between fingers 318 at the proximal end310 permit the fingers 318 to separate outwardly so as to accommodatethe annular section 320.

[0046] In the illustrative embodiment of FIG. 3, tabs 328 are providedon the annular section 320 that are sized and positioned so as to fitwithin the gaps 312 when the sheath 316 is attached to the upper housing202. This mating of the tabs 328 with the gaps 312 inhibits the sheath316 from rotating with respect to the upper housing 202 when attachedthereto. Alternatively, one or more other portions of the sheath (e.g.,one or more of the fingers 318) may be tabbed, and one or morecorresponding portions of the upper housing 202 (e.g., one or moresections of the annular section 320) may be slotted, or vice versa, sothat the mating of the “tabs” with the “slots” inhibits the sheath 316from rotating or otherwise moving with respect to the upper housing 202once these components are locked into engagement.

[0047] In one embodiment, the sheath 316 is rigid so that, when thesupport member 314 is accommodated by the sheath 316, the support member314 is permitted to rotate within the sheath 316, and the sheath 316remains spaced from the support member 314 throughout the supportmember's permitted range of rotation. Because the camera head 122 isattached to the support member 314, rotation of the support memberwithin the sheath 316 also causes the camera head 122 to rotate withinthe sheath 316 so that the azimuth of the camera head 122 can beadjusted while the sheath remains stationary with respect to the subjectbeing viewed. In the illustrative embodiment of FIG. 3, the elevation ofthe camera head 122 also can be adjusted within the sheath 316 withoutmoving the sheath 316 with respect to the subject being viewed. Asdiscussed in more detail below, this ability to move the camera head 122so that the imaging axis 326 is oriented in virtually any directionwhile keeping the sheath 316 stationary with respect to the subjectbeing viewed provides significant advantages.

[0048] In one embodiment for use in medical applications, the sheath 316is sterile so that, when it is attached to the upper housing 202, itcreates a sterile barrier between the elements accommodated by thesheath (e.g., the support member 314 and the camera head 122) and theenvironment outside the sheath 316 (e.g., the patient's torso 200 ofFIG. 2). In such an embodiment, because of this sterile barrier, it isnot necessary to sterilize the components accommodated by the sheath316, which provides significant advantages over prior art imagingsystems in which such sterilization is required. For example, becausesome components need not be sterilized between procedures, thesecomponents are immediately available for subsequent procedures, and thephysician does not have to wait for the components to be sterilizedbefore re-use. Rather, the physician may immediately begin a newprocedure by using a new (or newly-sterilized) sterile sheath 316 incombination with the previously-used, unsterile components.Additionally, because some components of the camera 106 need not besterilized between uses, the risk that these components will be damagedduring the sterilization process is eliminated.

[0049] In one embodiment, a flexible, sterile drape (not shown) isattached to the sheath 316 (e.g., over a rim portion 304 of the sheath316). Such a drape may be extended proximally over the upper housing 202and a cord (not shown) coupling the camera 106 to the camera controller102 so that the sheath 316 and the drape together create a sterilebarrier between all components of the camera 106 and the subject beingviewed.

[0050] In one embodiment of the present invention, an optically clearmaterial (e.g., plastic or glass having an “S1” finish), is used to formthe sheath to ensure that the sheath does not degrade the quality of theimage viewed by the camera. It should be appreciated that, when thesheath 316 is used in a camera such as that shown in FIG. 2, the imagingaxis of the camera may pass only through certain portions of the sheathwhen the camera is in operation. In the embodiment of FIGS. 2-3, forexample, when the camera 106 is being used, the imaging axis 326 passesonly through a small portion 322 (FIG. 3) of the sheath 316 near thecamera's distal end 204. In another embodiment of the invention,optically-clear materials are used only for the portion(s) of the sheaththat affect the quality of the image sensed by the camera, and lessexpensive materials are used for the remaining portions of the sheath.In the illustrative embodiment of FIGS. 2 and 3, for example, only thesmall portion 322 (e.g., a length of “1.25” inches) of the sheath 316can be made of an optically-clear material, and the remainder of thesheath 316 can be formed (e.g., as an opaque extrusion) from low-costplastic, glass and/or other low-cost materials. By producing the sheathsin such a low-cost manner, each sheath 316 may, if desired, be disposedof after a single use. It should be appreciated that, in alternativeembodiments, materials other than those mentioned may be used to makethe sheath 316, and the invention is not limited to the specificmaterials identified.

[0051] The optically-clear portion 322 of the sheath 316 may be securedto the opaque portion of the sheath 316 in any of numerous ways, and theinvention is not limited to any particular securing technique. Forexample, in one embodiment, the optically-clear portion 322 is securedto the non-optically-clear portion using an epoxy. Alternatively, theoptically-clear portion 322 may be secured to the non-optically-clearportion using sonic-welding, press-fitting, or any other technique.

[0052] In one embodiment, the curvature of the distal end of the sheath316 is spherical so that, when the camera head 122 rotates about a pivotpoint 324 (as described below), the head remains a constant distancefrom the inner surface of the sheath 316, and an imaging axis 326, alongwhich the camera head 122 senses an image, remains normal to the innersurface of the sheath. In this manner, the angle at which the imagingaxis 326 intercepts the inner surface of the sheath 316 does not changeas the camera head 122 moves within the sheath 316, and does not causethe image sensed by the camera head 122 to be distorted.

[0053] While sheaths having specific characteristics and specificmanufacturing techniques for producing such sheaths have been describedherein, it should be appreciated that the invention is not limited tothe particular sheaths or the particular manufacturing techniquesdescribed.

[0054]FIG. 4 is a perspective, sectional view of the upper housing 202of FIGS. 2-3 according to one embodiment of the invention. In theillustrative embodiment of FIG. 4, the upper housing 202 includes twoseparate housing portions 202 a and 202 b which are mated together. Theportions 202 a-b may be secured together in any of numerous ways, andthe invention is not limited to the use of any particular securingtechnique. In one embodiment, for example, the sections 202 a-b aresecured together using an epoxy. Alternatively, the sections 202 a-b maybe sonic-welded, press-fit, or otherwise secured together.

[0055] As mentioned above, according to one aspect of the invention,each of a pair of actuators (e.g., step motors) is included within asingle actuator module that can be inserted in and removed from theupper housing 202 as a unit. The illustrative embodiment of FIG. 4incorporates this aspect of the invention by the use of an actuatormodule 402 which includes a pair of step motors 118 a-b. FIG. 5 showsthe actuator module 402 separated from the upper housing 202.

[0056] As discussed above, in one embodiment of the invention, thesupport member 314 is rotatable within the sheath so that the azimuth ofthe camera head 122 can be adjusted without moving the sheath 316 withrespect to the subject being viewed. Another advantageous feature of thecamera 106 (as illustrated best in FIG. 4) is that rotation of thesupport member 314 can also be accomplished without rotating the upperhousing 202 with respect to the subject being viewed. That is, in theillustrative embodiment of FIG. 4, the upper housing 202 and the sheath316 are held stationary with respect to one another, and the actuatormodule 402 and the support member 314 (which are held stationary withrespect to one another) rotate as a unit within the upper housing 202and the sheath 316. In this manner, all external portions of the camera106 remain stationary with respect to the subject being viewed, and onlyportions internal to the camera 106 move with respect to the subjectwhen the position of the camera head 122 is adjusted.

[0057] The rotation of the actuation module within the upper housing 202may be effected in any of numerous ways, and the invention is notlimited to any particular technique for accomplishing this result. Inthe FIG. 4 embodiment, for example, the actuation module is rotatablymounted within the upper housing using a bearing ring assembly 412 (alsoshown in FIGS. 6A-B) interposed between the actuator module 402 and aninner surface of the upper housing 202. As shown in the illustrativeembodiment of FIGS. 4 and 6, the bearing ring assembly 412 includes anouter ring 412 a, an inner ring 412 b, and a plurality of ball bearings412 c sandwiched therebetween. In this configuration, the outer ring 412a is permitted to rotate freely about the inner ring 412 b.

[0058] As is illustrated best in FIG. 6A, a pair of locking members 412d of the bearing ring assembly 412 engage corresponding notches 602 inthe inner surface of the upper housing 202, thereby preventing the outerring 412 a from moving with respect to the upper housing 202. Similarly,a pair of locking members 412 e engage corresponding notches 604 in theactuator module 402 so as to prevent the inner ring 412 b from movingwith respect to the actuator module 402. Thus, because of the presenceof the bearing ring assembly 412, the actuator module 402 is permittedto rotate freely within the upper housing unit 202.

[0059] While the bearing ring assembly 412 is described herein as beingused for a specific application, i.e., an actuator module that isrotatable within a camera housing, it should be appreciated that theinvention is not limited in this respect. Rather, the bearing ringassembly 412 may be used in any application wherein a rotationalrelationship between two or more components is desired. Although bearingring assemblies are known, it is believed that the use of one or moremating features such as the locking members 412 d and 412 e that permiteither (or both) of the bearing rings to be held in a fixed physicalrelationship with another component represent a notable advancement overthe state of the art. Therefore, a ring assembly having such featurescan be used in any numerous other applications wherein bearing rings areemployed.

[0060] In the illustrative embodiment of FIG. 4, the actuator module 402has a gear 408 rotatably secured to a top portion 428 thereof so as topermit the gear 408 to rotate with respect to the actuator module 402.An upper extension 426 of the gear 408 is fixably secured within acorresponding cavity 410 in the upper housing 202 so that the gear 408is not permitted to rotate with respect to the upper housing 202.

[0061] One of the motors included in the actuator module 402 of FIGS.4-6 is an azimuth motor 118 a having a gear 406 attached to a driveshaft thereof so that the gear 406 rotates when the azimuth motor 118 ais activated. In the illustrative embodiment shown, the gear 406 ismated with the gear 408 so that, when the azimuth motor 118 a isactivated, the rotation of the gear 406 causes the entire actuatormodule 402 and the inner ring 412 b to rotate with respect to the upperhousing 202 and the outer ring 412 a.

[0062] In the FIG. 4 embodiment, a proximal end 430 of the elongatedsupport member 314 is secured within a corresponding cavity 432 at thedistal end of the actuator module 402 so that the elongated supportmember 314 is held stationary with respect to the actuator module 402.Therefore, when the actuator module 402 is caused to rotate within theupper housing 202, the elongated support member 314 is also caused torotate with respect to the upper housing 202.

[0063] As discussed above, the proximal end 310 of the sheath 316 may besecured to the distal end 302 of the upper housing 202. In oneembodiment, the sheath 316 is fixedly secured to the upper housing 202so that the sheath 316 is held stationary with respect to the upperhousing 202. Therefore, when the actuator module 402 is caused to rotatewithin the upper housing 202, the elongated support member 314 is causedto rotate within the sheath 316.

[0064] When the communication link 130 (FIG. 1) between the camera 106and the camera controller 102 comprises a multi-conductor cord, thiscord may pass through a hole 404 (FIG. 4) in the upper housing 202 andmay be held therein using a rubber grommet or the like. Individual wiresof this cord may be connected to the actuators 118 a-b, the signalconditioning circuit 120 and one or more lights (described below inconnection with FIG. 8). In one embodiment, the rotation of the actuatormodule 402 within the upper housing 202 is limited to plus or minus“180” degrees so as to prevent the wires in the upper housing frombecoming stretched, broken, or tangled. Alternatively, slip rings may beemployed to establish electrical connections so that the actuator module402 is permitted to rotate within the upper housing 202 withoutlimitation. When the communication link 130 is wireless, a transceiver(not shown) may be provided in the upper housing 202 to permit thecamera controller to communicate with the components of the camera 106.

[0065]FIG. 7 illustrates one exemplary implementation of a mechanicalassembly that may be employed in the camera 106 to cause the camera head122 to move to alter a viewing area 704 thereof. Referring to FIG. 7 inconjunction with FIG. 4, it can be seen how activation of the azimuthmotor 118 a (which causes the elongated support member 314 to rotatewithin the sheath 316) causes the camera head 122 to rotate within thesheath 316, thereby adjusting an azimuth position the camera head 122and altering the viewing area 704 thereof. Because rotation of thesupport member 314 causes the azimuth of the camera head 122 to beadjusted, the support member 314 serves as one of the mechanical links132 (FIG. 1) which serves to transfer physical forces from the azimuthmotor 118 a to the camera head 122.

[0066] In the illustrative embodiment of FIG. 4, the actuator module 402also includes an elevation motor 118 b. In the FIG. 4 example, athreaded member 420 is coupled to a drive shaft (or is itself the driveshaft) of the elevation motor 118 b so that activation of the elevationmotor 118 b causes the threaded member 420 to rotate. In the FIG. 4embodiment, the threaded member 420 is threaded within a correspondingthreaded hold 422 in an arm 418. The end of the arm 418 that includesthe hole 422 is contained within a cavity 434 located in the distalportion of the actuator module 402 such that the arm 418 is permitted tomove distally and proximally (i.e., up and down) within the cavity 434,but is not permitted to move sideways within the cavity 434. Therefore,activation of the elevation motor 118 b causes the threaded member 420to rotate within the threaded hole 422, causing the arm 418 to movedistally and proximally with respect to the actuator module 402. In theFIG. 4 embodiment, a proximal end of an actuation rod 424 is insertedthrough a second hole 436 in the arm 418, and is fixedly secured thereinso that the actuation rod 424 is held stationary with respect to the arm418. Thus, in the illustrative embodiment shown, movement of the arm 418distally and proximally causes the actuation rod 424 to move distallyand proximally within the sheath 316.

[0067] In the illustrative embodiment of FIG. 7, a distal end 716 of theactuation rod 424 has a hole 708 therein through which an upper portionof a bail 706 is inserted so that the bail 706 is permitted to rotatewithin the hole 708. As illustrated in FIG. 7, a lower portion of thebail 706 may be movably connected to a pair of arms 712 extending from arear portion of the camera head 122. In the FIG. 7 embodiment, at leastone arm 702 (partially cut away in FIG. 7) of the elongated supportmember 314 is pivotally connected to a pivot point 324 on a side of thecamera head 122 so that the camera head 122 is permitted to pivot aboutthe pivot point 324. Therefore, the distal and proximal movement of theactuation rod 424 (in response to the elevation motor 118 b beingactivated) causes the elevation of the camera head 122 and the viewingarea 704 thereof to be adjusted. Because movement of the actuation rod424 causes the elevation of the camera head 122 to be adjusted, theactuation rod 424 serves as another of the mechanical links 132 (FIG. 1)which serves to transfer physical forces from the azimuth motor 118 b tothe camera head 122.

[0068] The range of elevations through which the camera head 122 can beoriented, by pivoting about pivot point 324 (FIG. 7), may vary dependingon the physical configuration of the camera 106 and the application forwhich the camera 106 is being used. In the embodiment of FIGS. 2-7, forexample, in which the camera 106 is designed for use in an endoscopicsurgical procedure, the camera head 122 pivots through an angle ofapproximately “175” degrees about the pivot point 324. The camera can beconsidered as including a reference axis 718 that extends along alongitudinal axis of the support member 314. In one embodiment of theinvention, the camera 122 can be pivoted to form any angle between theimaging axis 326 (FIG. 3) and the reference axis 718 up to a maximum of“165” degrees. The elevation limit of “165” degrees from the referenceaxis 718 defines the elevation angle at which the viewing area 704begins to encompass the camera 106 itself, rather than the subjectmatter to be viewed. In addition, to ensure that the support shaft neednot be repeatedly rotated when viewing an area substantially in-linewith the reference axis 718, in one embodiment of the invention thecamera 122 can also be pivoted in the opposite direction to form anyangle between the imaging axis 326 (FIG. 3) and the reference axis 718up to a maximum of “10” degrees.

[0069] It should be appreciated that, although a particular range ofpivoting of the camera head 122 has been described in connection withthe embodiment of FIGS. 2-7, the invention is not limited in thisrespect. In alternative embodiments, the camera 106 can be configuredsuch that the camera head 122 can be oriented throughout a wider ornarrower range of elevations than that described. Preferably, the camera106 is configured such that the imaging axis 326 of the camera head 122is capable of being elevated to an angle of at least “45” degrees fromthe reference axis 718, more preferably to an angle of at least “90”degrees, and even more preferably to an angle of at least “135” degrees.

[0070] In operation, when the distal end 204 of the camera 106 isinserted, for example, into a body of a patient, a user who is viewingan object 714 (located in the viewing area 704) on the display 104(FIG. 1) is able to use the camera remote-control 108: (1) to activatethe azimuth motor 118 a to adjust the azimuth of the camera head 122,and (2) to activate the elevation motor 118 b to adjust the elevation ofthe camera head 122. The user therefore is permitted to view virtuallyany position within the area of interest in the patient's body, withoutrequiring the sheath to be moved or rotated within the patient's body.This ability to adjust the viewing area 704 without moving the sheath316 within the patient's body can be particularly advantageous becausefriction between the sheath and the patient's body can cause tissuedamage and/or irritation.

[0071] With respect to the above-described actuators and mechanicallinks used to adjust the elevation and azimuth of the camera head 122,it should be understood that these are only examples of mechanisms thatcan be used to cause the camera head 122 to move within the sheath 316,and that the invention is not limited to the use of the particularcamera-position control mechanisms described. Other types of actuatorsand/or mechanical links that perform similar functions may alternativelybe employed. Also, it should be understood that the invention is notlimited to embodiments in which one actuator controls the azimuth of thecamera head 122 and another actuator controls its elevation. Inalternative embodiments, for example, one actuator may cause the camerahead 122 to pivot about a first pivot axis in a first plane, and anotheractuator may cause the first plane to pivot about a second pivot axisthat is transverse to the first pivot axis. It should further beappreciated that multiple actuators need not be employed in allembodiments, and that the camera head 122 may alternatively be caused tomove in only a single plane, or may otherwise have a lesser range ofmotion than that described above.

[0072] In one embodiment of the invention, the camera 106 includes anon-board lighting scheme that permits the camera 106 to be used inpoorly illuminated areas, e.g., inside a patient's body, withoutrequiring a separate light source to be provided to illuminate the areabeing viewed. FIG. 8 illustrates an example of such a lighting scheme.In the illustrative embodiment of FIG. 8, a set of seven diffused lights802 a-g are powered via the connection 134, and are disposed on one sideof the elongated support shaft 314 so that a relatively wide area 806 onthat side of the support shaft is illuminated. It should be understood,however, that in alternative embodiments, additional or fewer diffusedlights may be used, and the diffused lights may be arranged inconfigurations (e.g., on both sides of the support shaft 314) other thanthat shown in FIG. 8.

[0073] In the FIG. 8 embodiment, in addition to the diffused lights 802a-g, a pair of focused lights 804 a-b are disposed on either side of thecamera head 122 so that the viewing area 704 is particularly wellilluminated by these focused lights 804 a-b. As shown, the lights 804a-b may be secured to the camera head 122 so as to move with the camerahead 122 and be illuminating the viewing area 704 at all times. As withthe diffused lights 802, it should be appreciated that the invention isnot limited in this respect, and that, in alternative embodiments,additional or fewer focused lights may be used, and the focused lightsmay be arranged in any of a number of alternative configurations. Also,it should be appreciated that some embodiments may include only diffusedlights, or only focused lights, and that the invention is not limited toembodiments that employ both.

[0074] When the camera 106 is moved to a location that is at a lowertemperature than the environment from which the camera 106 was moved,the temperature difference may cause the atmosphere inside the sheath316 to cool, thereby causing condensation to form on an inner surface ofthe sheath 316. Such a phenomenon can occur, for example, when thecamera 106 is inserted into a cavity of a patient's body that has beeninsufflated with air, carbon dioxide, or other gas(es), because the flowof gas into the cavity tends to cause the cavity to become colder thanboth the atmosphere outside the patient's body and the patient's normalbody temperature.

[0075] In one embodiment, one or more of the lights 802 a-g and 804 a-bcan be selected to produce a sufficient amount of heat to inhibitmoisture from condensing on the inner surface of the sheath 316 when thecamera 106 is inserted into a cavity that is colder than the environmentin which the camera was previously located. For example, in embodimentsof the invention for use in surgical applications, one or more of thelights 802 a-g and 804 a-b may be selected and/or controlled to produceenough heat to prevent any moisture from condensing on the surface ofthe sheath 316 when the system is inserted in a patient's body bymaintaining the temperature within the sheath above a normal bodytemperature (e.g., “37” degrees Celsius). In one embodiment, in order tocomply with current guidelines of the United States Food and DrugAdministration, the heat generated by the focused lights 804 a-bmaintains the temperature within the sheath: (a) above “37” degreesCelsius throughout the sheath, (b) below “45” degrees Celsius near thecamera's distal end 204, and (c) below “41” degrees Celsius near theproximal end 310 of the sheath 316. It should be appreciated, however,that the amount of heat generated may be adjusted to comply withdifferent guidelines, or may be adjusted for use in environments otherthan a patient's body.

[0076] In the illustrative embodiment of the invention shown in FIGS.7-9, the connection 134 between the signal-conditioning circuit 120 andthe camera head 122 is formed using a multi-conductor flexible cable.Signals from the image sensor 124 (e.g., a CCD), as well as powersignals for the diffused lights 802 a-g and the focused lights 804 a-b,may be fed through this flexible cable. As shown in FIG. 7, the imagesensor 124 may comprise a CCD to which the flexible cable is connected.In embodiments of the invention that employ a flexible cable as theconnection 134, the optical elements in the camera head 122 that focusand receive light from an image being sensed (e.g., the lens assembly128 and the image sensor 124) need not be in-line with the signalconditioning circuit 120 or other elements of the camera 106, and can bepositioned independently therefrom. This is in contrast to aconventional camera in which the lens, the viewing aperture and therecording medium (e.g., film) are optically aligned within the body ofthe camera. Because the camera head 122 can be positioned independentlyfrom the other elements of the camera 106, the camera head 122 can berotated within the distal end of the sheath 316 without also rotatingthe other camera elements therein. This feature enables the distal end204 of the camera 106 to be smaller than if all of the components of thecamera 106 were required to rotate in unison within the sheath 316.Although using a flexible circuit as the connection 134 providesnumerous advantages, it should be appreciated that the invention is notlimited in this respect, and that the connection 134 may be formed usinga number of alternative types of connectors.

[0077] As mentioned above, according to one aspect of the invention, thesignal-conditioning circuit 120, the connection 134, and the camera head122 of the camera 106 (FIG. 1) all are included within a single cameramodule which may be inserted in and removed from the camera 106 as aunit. The embodiment of FIGS. 7-9 incorporates this aspect of theinvention by employing a camera module 902 (see FIG. 9) which includesthe amplifier circuit 120 (not shown in FIG. 8), the flexible cable 134,and the camera head 122. FIG. 9 shows an example of how the cameramodule 902 may appear when separated from the other components of thecamera 106. Although not illustrated in FIG. 9, in some embodiments, thediffused lights 802 a-g and/or the focused lights 804 a-b may also beincluded in the camera module 902. In embodiments of the invention thatemploy the camera module 902 of FIGS. 7-9, when any one of theconstituent components of the camera module 902 fails, the entire cameramodule 902 may be swapped for a new camera module so that the camera 106may still be used while the swapped-out camera module is being repaired.

[0078] The lens assembly 128 (FIG. 1) may be configured in any of anumber of ways, and the invention is not limited to any particularconfiguration. In one embodiment, the lens assembly 128 acts as aconstant focus lens and does not require any focusing or positioningmechanism. Because focusing a lens typically requires components of thelens assembly to be moved over a certain distance, and requires afocusing mechanism which consumes space, the use of a constant focuslens enables the distal end of a camera (such as the endoscopic camera106) employing this type of lens assembly to be made smaller than afocused lens assembly. FIG. 10 shows an illustrative example of aconstant focus lens assembly.

[0079] In the FIG. 10 example, the lens assembly 128 may be employed tofocus an image onto the image sensor 124 (e.g., a CCD) within the camerahead 122. An example of how the lens assembly 128 may be positioned withrespect to the other components in the camera 106 is shown in FIG. 8. Asshown in FIG. 10, the lens assembly 128 may include a lens housing 1002,and several lenses 1020, 1030, 1040 supported thereby. FIG. 11illustrates how the lenses 1020, 1030, 1040 may be used to focus lightonto the image sensor 124.

[0080] In one embodiment, an outer surface 1080 of the lens housing 1002is threaded so that the lens housing 1002 may be screwed into positionwithin a correspondingly threaded cavity (not shown) within a camerahousing 808 (FIG. 8) that also supports the image sensor 124. In thismanner, the distance between the lens assembly 128 and the image sensor124 may be optimized by rotating the threaded lens housing 1002. Oncethis distance is optimized, the lens housing 1002 may be secured withinthe camera housing 808, for example, using an epoxy adhesive. In oneembodiment, an adhesive that forms a bond that can be readily brokenwhen heated or otherwise subjected to an abnormal environmentalcondition may be used so that the lens assembly 128 can be readilyreplaced if defective.

[0081] The lens assembly 128 provides a constant focus lens array whichcan be used to focus light from a target onto an the image sensor 124.Optically, one embodiment of the lens assembly 128 has an effectivefocal length of “3.53” mm in air, an F number of “11.2,” and an angle ofview of “34” degrees. These optical characteristics permit highresolution images to be taken of any object that is more thanapproximately one inch away from the lens assembly 128 without requiringthe use of focusing or lens positioning equipment. Because the lensassembly 128 does not require any sort of lens positioning equipment tofocus light on the CCD, the lens assembly 128 can be quite small (e.g.,in one embodiment, the lens assembly 128 is less than “5” mm in diameterand less than “5” mm in depth). This permits the lens assembly 128 to beused in a variety of different devices. For example, the small size ofthe lens assembly 128 is advantageous for use in the camera 106 of FIGS.2-9 used in minimally-invasive surgical/diagnostic procedures. The lensassembly 128 may also be advantageously used in any of numerous otherapplications, e.g., videoscopes or surveillance equipment. Examples ofsuch alternative applications are described in co-pending patentapplication Ser. No. 09/126,368, which is hereby incorporated herein byreference. While other lens assemblies may be capable of achievingsimilar optical characteristics, such lens assemblies would generallyinclude a greater number of distinct lenses, thus preventing them frombeing used in devices where it is desirable to minimize the physicaldimensions of the lens assembly.

[0082] As shown in the illustrative embodiment of FIGS. 10-11, the lensassembly 128 may include a distal lens 1020, a doublet lens 1030(including component lenses 1030 a-b), and a proximal lens 1040. Asshown, the lens assembly 128 may also include an outer lens 1010 tofurther focus light received from a target. The outer lens 1010 may, forexample, be formed from a polycarbonate material having a radius ofcurvature of “5” mm, a thickness of “0.381” mm, and a diameter of “10”mm. In one embodiment, the outer lens 1010 comprises a part of thesheath 316 (FIG. 3). Alternatively, the outer lens 1010 may be housed bythe lens housing 1002 of FIG. 10.

[0083] In the illustrative embodiment shown, the distal lens 1020 is aconvex/concave lens that may be formed, for example, from SFL56 typeoptical glass having a thickness of “0.53” mm. The convex surface of thedistal lens 1020 may have a radius of curvature of “1.3” mm, and theconcave surface of the distal lens 1020 may have a radius of curvatureof “2.378” mm. When used in conjunction with the outer lens 1010, thelens 1020 may be separated from the outer lens 1010 by a space of “0.3”mm.

[0084] In the embodiment of FIGS. 10 and 11, the lens 1030 is a doubletlens including component lenses 1030 a-b that are formed from twodifferent types of glass. The lens 1030 a may, for example, be formedfrom SK18A type optical glass having a thickness of “0.919” mm, and thelens 1030 b may, for example, be formed from SFL56 type optical glasshaving a thickness of “0.657” mm. The concave surface of the lens 1030 amay, for example, have a radius of curvature of “0.948” mm, and theconvex surface of the lens 1030 a may, for example, have a radius ofcurvature “1.052” mm. The concave surface of the lens 1030 b may, forexample, have a radius of curvature of “1.052” mm (i.e., the same as theconvex surface of the lens 1030 a), and the convex surface of the lens1030 b may, for example, have a radius of curvature of “1.7162” mm.

[0085] The lenses 1030 a may be cemented together using an opticalcement (e.g., NORLAND 61), and the doublet lens 1030 may be separatedfrom the distal lens 1020, for example, by a distance of “0.533” mm. Thedistance between the distal lens 1020 and an aperture stop 1125 (seeFIG. 11) of the lens assembly 128 (i.e., the plane at which the lightrays converge) may, for example, be “0.2” mm, and the distance betweenthe aperture stop 1125 and the doublet lens 1030 may, for example, be“0.333” mm.

[0086] In the illustrative embodiment of FIGS. 10-11, the proximal lens1040 is a bi-convex lens that may be formed, for example, from SK18Atype optical glass having a thickness of “1.500” mm. The radius ofcurvature of each of the convex surfaces of the proximal lens 1040 may,for example, be “6.063” mm. This permits the proximal lens 1040 to bemanufactured at a low cost, as similar fabrication procedures can beused for each surface. Furthermore, production of the proximal lensassembly 128 is facilitated and manufacturing defects are reducedbecause the proximal lens 1040 cannot be inserted in the wrongorientation. That is, when both surfaces of a lens have the same shape(i.e., bi-concave or bi-convex) and differ only in their radius ofcurvature, it is difficult to distinguish one surface of the lens fromthe other. In the illustrative embodiment shown, the proximal lens 1040is separated from the doublet lens 1030 by a space of “0.1” mm, and isseparated from image sensor 124 by a space of “0.758” mm. Although notshown in FIGS. 10-11, each of the lenses 1020, 1030 and 1040 may includean anti-reflective coating on its outermost surface.

[0087] It should be appreciated that the materials and dimensions of thelens assembly 128 described above are exemplary only, as the dimensionsof the lenses 1010, 1020, 1030, 1040, the types of optical glass, andthe separation distances between the lenses may be varied. The exampleglass types given above, i.e., optical glass types SFL56 and SK18A, areavailable from Schott Glass Technologies, Inc. of Duryea Pa. Opticalglass types from other manufacturers may alternatively be used, althoughother manufacturers may have different designations for optical glasstypes having similar optical characteristics to those described above.In general, the optical characteristics that are most significant arethe index of refraction and the V number (i.e., the ABBE value) of theglass. The polycarbonate material used for the outer lens 1010 may, forexample, have an index of refraction of “1.585” and a V number of“29.9,” the SFL56 type optical glass may, for example, have an index ofrefraction of “1.785” and a V number of “26.1,” and the SK18A typeoptical glass may, for example, have an index of refraction of “1.639”and a V number of “55.4.” While the particular embodiment of the lensassembly 128 described in connection with FIGS. 10-11 has significantadvantages, it should be appreciated that any of numerous other types oflens assemblies having different numbers and/or types of components mayalternatively be employed, and that the invention is not limited to theparticular embodiment of the lens assembly 128 described above.

[0088] In one embodiment of the present invention, the lens assembly 128is used with an image sensor 124 (e.g., a CCD) that includes one or moreoptical surfaces 1050, 1060 that are separated from a pixel array 1070of the image sensor 124 (FIGS. 10-11). An example of such an imagesensor 124 is the GPKS 462 model CCD from Panasonic. The opticalsurfaces 1050, 1060 may include one or more filters (i.e., an infraredfilter, an antialiasing filter, etc). The image sensor 124 may alsoinclude a plurality of microlenses 1065 that are used to increase thesensitivity of the pixel elements in the pixel array 1070. Such imagesensors having microlenses 1065 covering the pixel elements of the pixelarray 1070 have become increasingly popular. However, applicants havefound that conventional lens systems are not well suited for use withsuch image sensors. In particular, applicants have determined that whenthe light incident on the outermost surface of an image sensor (e.g.,the surface 1050) is more than approximately ten degrees fromperpendicular, the pixel elements of the image sensor can fail toadequately and uniformly image a target. That is, due to the presence ofthe microlenses 1065, the amount of light detected by the pixel elementsat the outer edges of the array can be less than that detected by thepixel elements in the center of the array, even when viewing a uniformlylit target. However, the lens assembly 128 described above isparticularly well suited for use with image sensors having suchmicrolenses 1065 covering the pixel array 1070 because the lens assembly128 focuses light so that it is nearly perpendicular to the outermostsurface 1050 of the image sensor 124, even at the outer edges of theimage sensor (i.e., the lens assembly is telocentric in image space). Itshould be appreciated that although the lens assembly 128 isparticularly well suited for use with this type of image sensor, theinvention in not limited in this respect, and that any of numerousalternative types of image sensors (with or without microlenses 1065 andthe other above-described features) may be employed.

[0089] In contrast to conventional scopes that are manually positionedwithin a remote area to be viewed (e.g., a patient's body cavity), thecamera remote-control 108 (FIG. 1) may be used to position the camerahead 122 within the cavity from a location outside the cavity. FIG. 12shows an example of a foot pedal control assembly 1202 that may beemployed as the camera remote-control 108. In the illustrativeembodiment of FIG. 12, the foot pedal control assembly 1202 includesfour controls: (1) an azimuth (left or right) control 1204; (2) anelevation (up or down) control 1206; (3) a zoom (in or out) control1208; and (4) a light intensity (dimmer or brighter) control 1210. Withrespect to the azimuth control 1204, the elevation control 1206, and thelight intensity control 1210, signals from the foot pedal controlassembly 1202 may be routed (via the camera controller 102) to thecamera 106 (FIG. 1). If necessary, the camera controller 102 may be usedto convert the signals from the foot pedal control assembly 1202 intosignals which are suitable to control the actuator(s) 118 and/or thelights 802, 804 within the camera 106. With respect to the zoom control1208, signals from the foot control assembly 1202 may be used to causethe camera controller 102 to adjust a relative portion of the sensedimage that is displayed on the display 104 (i.e., to digitally zoom) soas to adjust the zoom of the displayed image. Alternatively, amechanical zoom control (not shown), including an additional actuator118 (not shown) and an additional mechanical link 132 (not shown), maybe provided in the camera 106 to mechanically adjust a zoom of thecamera head 122 in response to signals from the camera remote-control108.

[0090] FIGS. 13-15 (in several different views) show an example ofanother remote-control device, i.e., a hand operated remote-controltouch panel 1300, which may be used as the camera remote-control 108. Inone embodiment for use in surgical applications, the remote-controltouch panel 1300 is constructed from medical-grade plastic that isprovided in a sterilized condition, and is intended to be disposed ofafter use. However, it should be appreciated that the remote-controltouch panel 1300 may alternatively be constructed from other materials,such as heat-resistant materials that allow it to be sterilized andre-used.

[0091] As shown in FIG. 13, the remote-control touch panel 1300 mayinclude a number of controls 1310-1360 for controlling the camera 106.Each of these controls provides a control signal that can becommunicated to the camera controller 102, for example, by a wire thatis connected to lead 1370. Alternatively, a wireless transmission medium(not shown) can be used to communicate the control signals to the cameracontroller 102. In the example shown, controls 1310 and 1315 adjust theelevation of the camera head 122, and controls 1320 and 1325 adjust theazimuth of the camera head 122. Also, in the FIG. 13 embodiment,controls 1330 and 1335 alter the field of view 704 (FIG. 7) of thecamera head by zooming in and out on the target 714 being imaged.

[0092] In the embodiment depicted, each of controls 1310-1335 can beactivated by depressing a raised button on an upper surface 1380 of thetouch panel. Because each button is raised above the plane of the touchpanel 1300, the person operating the camera 106 can control the camerausing only their sense of touch. This form of tactile feedback enablesthe operator (e.g., a surgeon) to focus his or her full attention on theprocedure being performed. Furthermore, each button can also includeraised lettering on the top surface of the button to further aidselection by the operator.

[0093] As shown in FIG. 13, the remote-control touch panel 1300 alsoincludes controls 1340-1360 for use in conjunction with a computerizedcontrol mechanism (e.g., the camera controller 102) to manipulate and/orstore the signals from the image sensor 124. As described further below,menu control 1340 enables the operator to select and adjust controlparameters that affect the quality of the image being displayed. Thecontrol 1350 enables the operator to store one or more snapshots of animage seen by the image sensor at a particular instant in time. Forexample, snapshots of the image can be stored by the memory 114 (FIG.1), which may comprise any form of storage medium (i.e., disk, tape,compact disk, etc.). The control 1360 can be used to cause the printer116 to print a snapshot of an image seen by the image sensor 124 at aparticular instant of time, or to print a copy of an image that has beenpreviously stored in the memory 114.

[0094] As noted above, menu control 1340 may enable the operator (e.g.,a surgeon) to control the quality of the image being displayed through aseries of pop-up menus that are displayed on a display device (e.g., thedisplay 104). For example, when the menu control 1340 is selected, a toplevel menu may be displayed that allows the operator to manipulate thenature of the picture being displayed, for example, by altering thebrightness, contrast, tint, color, etc. Controls 1310 and 1315 can beused to scroll up and down the top-level menu, and control 1350 can beused to select a particular sub-menu from the top-level menu. Uponselection of a particular sub-menu, controls 1320 and 1325 may be usedto increase and decrease the value of a particular display parameter,for example, the contrast of the image. Menu control 1340 may also beused to permit the operator to select a predefined set of preferreddisplay parameters, or to enable the operator to take advantage of thecapabilities of the camera controller 102 by performing other functions(e.g., transmitting an image captured by the system over a transmissionline (not shown) coupled to the camera controller 102).

[0095] In the embodiment shown in FIGS. 13-15, the remote-control touchpanel 1300 is formed from three layers of medical-grade plasticincluding an upper layer 1510, a lower layer 1530, and an intermediatelayer 1520. In the example shown, the upper layer 1510 includes aplurality of conductive contacts (e.g., 1361, 1316, 1336) correspondingto the plurality of controls 1310-1360. In the lower layer 1530,directly below each of these conductive contacts, is a correspondingcontact (e.g. 1460, 1415, 1435) that is connected to lead 1370 by arespective one of conductors 1480 (FIG. 14). Intermediate layer 1520separates the conductive contacts in the upper layer 1510 from theircorresponding contacts 1410-1460 in lower layer 1530. However, apertures1540 in the intermediate layer 1520 permit electrical conduction betweeneach set of corresponding contacts in the upper and lower layers whenthe corresponding control is depressed or activated.

[0096] In the embodiment shown in FIGS. 13-15, the lead 1370 may beintegrally formed as part of the lower layer 1530. This can simplify themanufacture of the remote-control touch panel by reducing the number ofdistinct elements in the design. Furthermore, as fewer distinct elementsneed to be aligned (i.e., each of conductors 1480 with one of theconductors in lead 1370) to form the touch panel, the cost ofmanufacturing the touch panel can be reduced, thereby allowing it to beeconomically disposed of after use.

[0097] In one embodiment of the present invention, the lower surface1490 (FIG. 14) of the touch panel is coated with an adhesive and coveredby a removable backing (not shown). Removal of the backing permits thetouch panel to be mounted to a supporting surface, such as an operatingtable, or the patient. In this manner, the remote-control touch panel1300 can be positioned where it is most conveniently used. Furthermore,because the remote-control touch panel 1300 is formed from flexiblematerials, the touch panel can be mounted to irregularly shaped surfacesas well as planar surfaces.

[0098] It should further be appreciated that the remote-control touchpanel 1300 in which the camera head 122 is positionable by theoperator's hands provides a number of advantages. For example, when usedby a surgeon, the remote-control touch panel can be mounted so that itis within the field of view of the surgeon during the surgicalprocedure. In addition, it can be mounted so that it is close to thesurgeon's hand during all phases of the surgical procedure.

[0099]FIG. 16 shows yet another example of a camera remote-control 108,i.e., a voice-activated remote-control 1600, which may be used toremotely control the camera 106. In the illustrative embodiment shown,the voice-activated remote-control 1600 includes a microphone 1610 whichis coupled to the camera controller 102 via a cable 1620. Alternatively,the voice activated remote-control 1600 may be coupled to the cameracontroller 102 via a wireless transmission medium.

[0100] Voice recognition software stored on the memory 114 may beexecuted by the processor 110 in the camera controller 102 to controlthe operation of the camera 106 in response to predefined oral commands.For example, the words “left” and “right” can be used to alter theazimuth of the camera head 122, while the words “up” and “down” can beused to alter the elevation of the camera head 122. Other commands mayalso be defined to adjust the field of view of the camera (e.g., “zoomin,” “zoom out”), adjust the intensity of the lights (e.g., “bright,”“dim”), and to store or print a picture. In this manner, the operator(e.g., a surgeon) can devote his/her full attention to the procedurebeing performed, as neither the operator's hands nor eyes are requiredto control the operation of the camera 106.

[0101] Regardless of the particular type of remote-control device thatis used as the camera remote-control 108, the camera remote-control 108may (as discussed above) be spaced apart from the camera 106, providinggreat flexibility in the placement of the camera remote-control 108.That is, the camera remote-control 108 may be positioned away from thecamera 106 and/or the camera controller 102 at a location where it canbe most conveniently accessed by the operator. In one embodiment, thecamera remote-control 108 includes an adhesive backing that permits itto be mounted to any supporting surface, including a patient, that isconvenient to the operator. Alternatively, the camera remote-control 108may be mounted to another device (e.g., a medical instrument) where itcan be conveniently accessed while using the other device.

[0102] Having described several embodiments of the invention in detail,various modifications and improvements will readily occur to thoseskilled in the art. Such modifications and improvements are intended tobe within the spirit and scope of the invention. Accordingly, theforegoing description is by way of example only, and is not intended aslimiting. The invention is limited only as defined by the followingclaims and the equivalents thereto.

What is claimed is:
 1. A camera, comprising: an image sensor; a sheath having first and second ends, the first end of the sheath being closed to form a cavity to accommodate the image sensor; and a housing adapted to mate with the second end of the sheath; wherein one of the housing and the second end of the sheath includes at least one tab, and the other of the housing and the second end of the sheath includes at least one slot, the at least one tab being adapted to mate with the at least one slot when the housing is mated with the second end of the sheath to inhibit the second end of the sheath from rotating with respect to the housing.
 2. The camera of claim 1, wherein: the sheath includes a plurality of gaps defining a plurality of fingers adapted to separate to accommodate a portion of the housing to attach the sheath to the housing; the at least one slot is one of the plurality of gaps; and the at least one tab is disposed on the housing.
 3. The camera of claim 1, wherein the at least one tab is included on the sheath and the at least one slot is included on the housing.
 4. The camera of claim 1, wherein the sheath is elongated.
 5. The camera of claim 4, wherein the image sensor is disposed adjacent the first end of the sheath.
 6. The camera of claim 5, wherein the sheath is rigid.
 7. The camera of claim 1, wherein the sheath is rigid.
 8. The camera of claim 1, further including at least one actuator, disposed within the housing, mechanically coupled to the image sensor to adjust a position of an imaging axis of the image sensor.
 9. The camera of claim 8, wherein the imaging axis of the image sensor passes through different portions of the sheath when the position of the imaging axis is adjusted by the at least one actuator.
 10. A camera, comprising: a sheath having an inner surface; an image sensor having an imaging axis; a support, at least partially disposed within the sheath, that supports the image sensor within the sheath such that the image sensor is rotatable about at least two axes of rotation with respect to the sheath through a range of orientations, wherein the imaging axis is oriented normal to the inner surface of the sheath throughout the image sensor's range of orientations.
 11. The camera of claim 10, wherein the sheath is elongated.
 12. The camera of claim 11, wherein the image sensor is disposed adjacent a distal end of the sheath.
 13. The camera of claim 12, wherein the sheath is rigid.
 14. The camera of claim 10, wherein the sheath is rigid.
 15. The camera of claim 10, wherein the support is arranged to rotate the image sensor through at least ninety degrees about each of its at least two axes of rotation.
 16. The camera of claim 10, further including a housing including at least one actuator, the housing being attached to the sheath and the at least one actuator being mechanically coupled to the image sensor to rotate the image sensor about at least one of its at least two axes of rotation.
 17. The camera of claim 16, wherein the at least one actuator includes a pair of actuators, each of the pair of actuators being mechanically coupled to the image sensor to rotate the image sensor about a respective one of its at least two axes of rotation.
 18. The camera of claim 17, wherein the support has a longitudinal axis that extends along a length of the sheath, and wherein one of the at least two actuators is arranged to rotate the support about its longitudinal axis.
 19. The camera of claim 16, wherein the imaging axis of the image sensor passes through different portions of the sheath when the position of the imaging axis is adjusted by the at least one actuator.
 20. The camera of claim 10, wherein the support has a longitudinal axis that extends along a length of the sheath, and wherein the support is rotatable within the sheath about its longitudinal axis.
 21. An actuation module for use with a camera including an image sensor that is rotatable about at least two axes of rotation, the actuation module comprising: a module base adapted to be removably mounted in the camera; and a pair of actuators mounted to the base so that the pair of actuators can be removed from and inserted into the camera as a single unit, each of the pair of actuators being adapted to rotate the image sensor about a respective one of the at least two axes of rotation.
 22. The actuation module of claim 21, in combination with the camera.
 23. The actuation module of claim 22, wherein the camera includes an elongated sheath in which the image sensor is disposed such that an imaging axis of the image sensor passes through a distal end of the elongated sheath.
 24. The actuation module of claim 23, wherein the camera includes an upper housing attached to a proximal end of the elongated sheath, and wherein the module base is adapted to be removably mounted in the upper housing.
 25. The combination of claim 22, further including a camera module for use in the camera, the camera module comprising: a camera module base adapted to be removably mounted in the camera; the image sensor, the image sensor being mounted to the camera module base; a cable mounted to the camera module base and coupled to the image sensor; and a signal conditioning circuit mounted to the camera module base and coupled to the cable to receive an electronic signal produced by the image sensor via the cable; whereby the image sensor, the cable, the signal conditioning circuit, and the camera module base are removable from and insertable into the camera as a single unit.
 26. A camera module for use in a camera, comprising: a module base adapted to be removably mounted in the camera; an image sensor mounted to the base; a cable mounted and coupled to the image sensor; and a signal conditioning circuit, mounted to the base, and coupled to the cable to receive, via the cable, an electronic signal produced by the image sensor; whereby the image sensor, the cable, the signal conditioning circuit, and the base are removable from and insertable into the camera as a single unit.
 27. The camera module of claim 26, further including at least one refractive lens mounted to the module base and arranged to focus an image onto the image sensor.
 28. The camera module of claim 26, further including at least one light mounted to the module base and arranged to illuminate a viewing area to be imaged.
 29. The camera module of claim 28, wherein the at least one light includes at least one diffused light.
 30. The camera module of claim 28, wherein the at least one light is a focused light which is configured and arranged to be focused primarily onto the viewing area.
 31. The camera module of claim 26, in combination with a sheath of the camera, wherein the camera module is adapted to be removably mounted in the sheath such that, when the camera module is mounted in the sheath, an imaging axis of the image sensor passes through the sheath.
 32. A camera, comprising: a sheath; an image sensor disposed within the sheath; and at least one light disposed within the sheath, the at least one light being adapted to generate sufficient heat to prevent condensation from forming on the sheath when the sheath is inserted into a body of a living patient.
 33. The camera as claimed in claim 32, wherein the at least one light is adapted to generate sufficient heat to cause a temperature within the sheath to be greater than thirty-seven degrees Celsius when the sheath is inserted into the body of the patient.
 34. The camera as claimed in claim 33, wherein the at least one light is adapted to generate heat such that the temperature within the sheath does not exceed forty-five degrees Celsius when the sheath is inserted into the body of the patient.
 35. The camera as claimed in claim 34, wherein the sheath includes a distal end and a proximal end, and wherein the at least one light is adapted to generate heat such that the temperature within the sheath does not exceed forty-one degrees Celsius at the proximal end of the sheath when the sheath is inserted into the body of the patient.
 36. A bearing ring assembly, comprising: a first ring; a second ring arranged concentrically with the first ring; and a plurality of ball bearings disposed between the first and second rings such that the first ring is permitted to rotate with respect to the second ring; wherein the first ring includes at least one first mating feature adapted to engage a first structure so that the at first ring is inhibited from rotating with respect to the first structure.
 37. The bearing ring assembly of claim 36, wherein: the first and second rings are arranged in a common plane; and the at least one first mating feature extends from the first ring in a direction transverse to the common plane.
 38. The bearing ring assembly of claim 37, wherein the at least one first mating feature includes a pair of tabs disposed on opposite sides of the first ring.
 39. The bearing ring assembly of claim 36, wherein: the first and second rings are arranged in a common plane; and the at least one first mating feature extends from the first ring in a direction perpendicular to the common plane.
 40. The bearing ring assembly of claim 38, wherein the at least one first mating feature includes a pair of tabs disposed on opposite sides of the first ring.
 41. The bearing ring assembly of claim 36, wherein the second ring includes at least one second mating feature adapted to engage a second structure so that the second ring is inhibited from rotating with respect to the second structure.
 42. The bearing ring assembly of claim 41, wherein: the first and second rings are arranged in a common plane; the at least one first mating feature extends from the first ring in a direction transverse to the common plane; and the at least one second mating feature extends from the second ring in a direction transverse to the common plane.
 43. The bearing ring assembly of claim 42, wherein: the at least one first mating feature includes a first pair of tabs disposed on opposite sides of the first ring; and the at least one second mating feature includes a second pair of tabs disposed on opposite sides of the second ring.
 44. The bearing ring assembly of claim 41, wherein: the first and second rings are arranged in a common plane; the at least one first mating feature extends from the first ring in a direction perpendicular to the common plane; and the at least one second mating feature extends from the second ring in a direction perpendicular to the common plane.
 45. The bearing ring assembly of claim 44, wherein: the at least one first mating feature includes a first pair of tabs disposed on opposite sides of the first ring; and the at least one second mating feature includes a second pair of tabs disposed on opposite sides of the second ring.
 46. The bearing ring assembly of claim 45, wherein the first pair of tabs extends from the first ring in a same direction that the second pair of tabs extends from the second ring.
 47. The bearing ring assembly of claim 44, wherein the at least one first mating feature extends from the first ring in a same direction that the at least one second mating feature extends from the second ring.
 48. The bearing ring assembly of claim 41, in combination with the first and second structures, wherein the first structure is rotatable with respect to the second structure.
 49. The combination of claim 48, wherein: the first structure comprises a housing in which the first and second rings are disposed; and the second structure is at least partially disposed within the housing.
 50. The combination of claim 49, wherein the second structure includes an actuator adapted to cause the second structure to rotate within the housing.
 51. The combination of claim 48, wherein the second structure includes an actuator adapted to cause the second structure to rotate with respect to the first structure.
 52. The bearing ring assembly of claim 36, in combination with the first structure and a second structure, wherein the first structure is rotatable with respect to the second structure. 